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Hi, Rakesh Kumar

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	User Input / Output				Save Notes	Easy
	Data Types				Save Notes	Easy
	If Else statements				Save Notes	Easy
	Switch Statement				Save Notes	Easy
	What are arrays, strings?				Save Notes	Easy
	For loops				Save Notes	Easy
	While loops				Save Notes	Easy
	Functions (Pass by Reference and Value)				Save Notes	Easy
	Time Complexity [Learn Basics, and then analyse in next Steps]				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Patterns				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	C++ STL				Save Notes	Medium
	Java Collections				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Count Digits				Save Notes	Easy
	Reverse a Number				Save Notes	Easy
	Check Palindrome				Save Notes	Easy
	GCD Or HCF				Save Notes	Easy
	Armstrong Numbers				Save Notes	Easy
	Print all Divisors				Save Notes	Easy
	Check for Prime				Save Notes https://www.naukri.com/code360/problems/check-prime_624934	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Factorial of N numbers				Save Notes	Easy
	Reverse an array				Save Notes	Easy
	Check if a string is palindrome or not				Save Notes	Medium
	Fibonacci Number				Save Notes	Easy
	Understand recursion by print something N times				Save Notes	Easy
	Print name N times using recursion				Save Notes	Easy
	Print 1 to N using recursion				Save Notes	Easy
	Print N to 1 using recursion				Save Notes	Easy
	Sum of first N numbers				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Hashing Theory				Save Notes	Medium
	Counting frequencies of array elements				Save Notes https://www.geeksforgeeks.org/problems/frequency-of-array-elements-1587115620/0	Easy
	Find the highest/lowest frequency element				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Selection Sort				Save Notes	Easy
	Bubble Sort				Save Notes	Easy
	Insertion Sort				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Merge Sort				Save Notes	Medium
	Recursive Bubble Sort				Save Notes	Easy
	Recursive Insertion Sort				Save Notes	Easy
	Quick Sort				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Largest Element in an Array				Save Notes	Easy
	Second Largest Element in an Array without sorting				Save Notes	Easy
	Check if the array is sorted				Save Notes	Easy
	Remove duplicates from Sorted array				Save Notes	Easy
	Left Rotate an array by one place				Save Notes	Easy
	Left rotate an array by D places				Save Notes	Easy
	Move Zeros to end				Save Notes	Easy
	Linear Search				Save Notes	Easy
	Find the Union				Save Notes	Medium
	Find missing number in an array				Save Notes	Easy
	Maximum Consecutive Ones				Save Notes	Easy
	Find the number that appears once, and other numbers twice.				Save Notes	Medium
	Longest subarray with given sum K(positives)				Save Notes GFG : https://www.geeksforgeeks.org/problems/longest-sub-array-with-sum-k0809/1 (with negative elemets)\nNINJAS : https://www.naukri.com/code360/problems/longest-subarray-with-sum-k_5713505 (with non-negative elemets)\nNINJAS : https://www.naukri.com/code360/problems/longest-subarray-with-sum-k_6682399 (with negative elemets)\n\n2 pointer only work for non negative but hash will work for both	Medium
	Longest subarray with sum K (Positives + Negatives)				Save Notes GFG : https://www.geeksforgeeks.org/problems/longest-sub-array-with-sum-k0809/1 (with negative elemets)\nNINJAS : https://www.naukri.com/code360/problems/longest-subarray-with-sum-k_5713505 (with non-negative elemets)\nNINJAS : https://www.naukri.com/code360/problems/longest-subarray-with-sum-k_6682399 (with negative elemets)\n\n2 pointer only work for non negative but hash will work for both	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	2Sum Problem				Save Notes	Medium
	Sort an array of 0's 1's and 2's				Save Notes	Medium
	Majority Element (>n/2 times)				Save Notes	Easy
	Kadane's Algorithm, maximum subarray sum				Save Notes	Easy
	Print subarray with maximum subarray sum (extended version of above problem)				Save Notes	Medium
	Stock Buy and Sell				Save Notes	Easy
	Rearrange the array in alternating positive and negative items				Save Notes	Medium
	Next Permutation				Save Notes	Medium
	Leaders in an Array problem				Save Notes	Easy
	Longest Consecutive Sequence in an Array				Save Notes	Medium
	Set Matrix Zeros				Save Notes	Medium
	Rotate Matrix by 90 degrees				Save Notes	Medium
	Print the matrix in spiral manner				Save Notes	Medium
	Count subarrays with given sum				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	4-Sum Problem				Save Notes	Hard
	Largest Subarray with 0 Sum				Save Notes	Medium
	Count number of subarrays with given xor K				Save Notes https://www.interviewbit.com/problems/subarray-with-given-xor/	Hard
	Merge Overlapping Subintervals				Save Notes	Medium
	Merge two sorted arrays without extra space				Save Notes	Medium
	Find the repeating and missing number				Save Notes	Hard
	Count Inversions				Save Notes	Hard
	Reverse Pairs				Save Notes	Hard
	Maximum Product Subarray				Save Notes	Easy
	Pascal's Triangle				Save Notes	Medium
	Majority Element (n/3 times)				Save Notes	Medium
	3-Sum Problem				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Binary Search to find X in sorted array				Save Notes	Easy
	Implement Lower Bound				Save Notes	Easy
	Implement Upper Bound				Save Notes	Easy
	Search Insert Position				Save Notes	Easy
	Floor/Ceil in Sorted Array				Save Notes	Medium
	Find the first or last occurrence of a given number in a sorted array				Save Notes	Easy
	Count occurrences of a number in a sorted array with duplicates				Save Notes	Easy
	Search in Rotated Sorted Array I				Save Notes	Medium
	Search in Rotated Sorted Array II				Save Notes	Medium
	Find minimum in Rotated Sorted Array				Save Notes	Medium
	Find out how many times has an array been rotated				Save Notes	Easy
	Single element in a Sorted Array				Save Notes	Easy
	Find peak element				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Find square root of a number in log n				Save Notes	Medium
	Find the Nth root of a number using binary search				Save Notes	Medium
	Koko Eating Bananas				Save Notes	Hard
	Minimum days to make M bouquets				Save Notes	Hard
	Find the smallest Divisor				Save Notes	Easy
	Capacity to Ship Packages within D Days				Save Notes	Hard
	Kth Missing Positive Number				Save Notes	Easy
	Aggressive Cows				Save Notes https://www.spoj.com/status/vamp_niklaus/	Hard
	Book Allocation Problem				Save Notes https://www.naukri.com/code360/problems/allocate-books_1090540	Hard
	Split array - Largest Sum				Save Notes	Hard
	Painter's partition				Save Notes	Hard
	Minimize Max Distance to Gas Station				Save Notes https://www.geeksforgeeks.org/problems/minimize-max-distance-to-gas-station/1	Hard
	Median of 2 sorted arrays				Save Notes	Hard
	Kth element of 2 sorted arrays				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Find the row with maximum number of 1's				Save Notes https://www.geeksforgeeks.org/problems/row-with-minimum-number-of-1s5430/1\nhttps://www.naukri.com/code360/problems/row-with-maximum-1-s_1112656	Easy
	Search in a 2 D matrix				Save Notes	Medium
	Search in a row and column wise sorted matrix				Save Notes	Medium
	Find Peak Element (2D Matrix)				Save Notes	Hard
	Matrix Median				Save Notes https://www.geeksforgeeks.org/problems/median-in-a-row-wise-sorted-matrix1527/1	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Remove outermost Paranthesis				Save Notes	Easy
	Reverse words in a given string / Palindrome Check				Save Notes	Easy
	Largest odd number in a string				Save Notes	Easy
	Longest Common Prefix				Save Notes	Easy
	Isomorphic String				Save Notes	Easy
	check whether one string is a rotation of another				Save Notes	Medium
	Check if two strings are anagram of each other				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Sort Characters by frequency				Save Notes	Easy
	Maximum Nesting Depth of Paranthesis				Save Notes	Easy
	Roman Number to Integer and vice versa				Save Notes	Easy
	Implement Atoi				Save Notes	Medium
	Count Number of Substrings				Save Notes	Medium
	Longest Palindromic Substring[Do it without DP]				Save Notes	Hard
	Sum of Beauty of all substring				Save Notes	Medium
	Reverse Every Word in A String				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Introduction to LinkedList, learn about struct, and how is node represented				Save Notes	Easy
	Inserting a node in LinkedList				Save Notes	Easy
	Deleting a node in LinkedList				Save Notes	Medium
	Find the length of the linkedlist [learn traversal]				Save Notes	Easy
	Search an element in the LL				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Introduction to DLL, learn about struct, and how is node represented				Save Notes	Easy
	Insert a node in DLL				Save Notes	Easy
	Delete a node in DLL				Save Notes https://www.naukri.com/code360/problems/delete-node-in-a-linked-list_1105578\n\ndeleting a node and returning a pointer is diffrent from, \njust deleting a node and not returning pointer as pointer should be same\n\nin deleting first try to handle root case sepratly as in that case we can just copy data from next node and delet the next node\nand if want to delete other than root node, then we should check for if we have to deleted root->next or not\n\nif not root pointer should be same and asked to delete the root node then there should be >=2 total node presemt in linked list	Medium
	Reverse a DLL				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Middle of a LinkedList [TortoiseHare Method]				Save Notes	Easy
	Reverse a LinkedList [Iterative]				Save Notes need 3 pointers	Easy
	Reverse a LL [Recursive]				Save Notes	Easy
	Detect a loop in LL				Save Notes	Medium
	Find the starting point in LL				Save Notes	Medium
	Length of Loop in LL				Save Notes	Easy
	Check if LL is palindrome or not				Save Notes	Medium
	Segrregate odd and even nodes in LL				Save Notes	Medium
	Remove Nth node from the back of the LL				Save Notes	Medium
	Delete the middle node of LL				Save Notes	Medium
	Sort LL				Save Notes do this before : merge two sorted linked list\nhttps://leetcode.com/problems/merge-two-sorted-lists/description/	Medium
	Sort a LL of 0's 1's and 2's by changing links				Save Notes	Medium
	Find the intersection point of Y LL				Save Notes	Medium
	Add 1 to a number represented by LL				Save Notes	Medium
	Add 2 numbers in LL				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Delete all occurrences of a key in DLL				Save Notes	Medium
	Find pairs with given sum in DLL				Save Notes	Medium
	Remove duplicates from sorted DLL				Save Notes curr->next=curr->next->next;\nin process of deleting next node, after setting next for current node, DO NOT FOREGET checking that if new next exist or not before setting its (curr->next)'s prev to curr \nif(curr->next)curr->next->prev=curr;	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Reverse LL in group of given size K				Save Notes	Hard
	Rotate a LL				Save Notes	Medium
	Flattening of LL				Save Notes	Hard
	Clone a Linked List with random and next pointer				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Sort a stack using recursion				Save Notes	Medium
	Reverse a stack using recursion				Save Notes	Easy
	Recursive Implementation of atoi()				Save Notes	Hard
	Pow(x, n)				Save Notes	Medium
	Count Good numbers				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Generate all binary strings				Save Notes	Medium
	Generate Paranthesis				Save Notes	Medium
	Print all subsequences/Power Set				Save Notes	Medium
	Learn All Patterns of Subsequences (Theory)				Save Notes the question is about find no of unique total subsequence in tc = O(N) and SC =O(1).	Medium
	Count all subsequences with sum K				Save Notes	Hard
	Check if there exists a subsequence with sum K				Save Notes	Medium
	Combination Sum				Save Notes	Medium
	Combination Sum-II				Save Notes	Medium
	Subset Sum-I				Save Notes	Medium
	Subset Sum-II				Save Notes for uniqueness : sort the original array and put the final result in a set of vector. \nSorting initial array gives final vector in sorted order so even if in original array one element comes multiple time and and among those any one used result same vector. as they all used in sorted order.\n\njust have to create all posible answer and put in set.	Medium
	Combination Sum - III				Save Notes	Hard
	Letter Combinations of a Phone number				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Palindrome Partitioning				Save Notes	Medium
	Word Search				Save Notes	Medium
	N Queen				Save Notes	Hard
	Rat in a Maze				Save Notes	Hard
	Word Break				Save Notes little bit DP is used \nwhen problem is to store all result then Dp might no be needed \nBut when they asked to return true or false then DP might be helpful
	M Coloring Problem				Save Notes	Hard
	Sudoko Solver				Save Notes	Hard
	Expression Add Operators				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Introduction to Bit Manipulation [Theory]				Save Notes	Easy
	Check if the i-th bit is set or not				Save Notes	Easy
	Check if a number is odd or not				Save Notes	Easy
	Check if a number is power of 2 or not				Save Notes	Easy
	Count the number of set bits				Save Notes	Easy
	Set/Unset the rightmost unset bit				Save Notes	Easy
	Swap two numbers				Save Notes	Easy
	Divide two integers without using multiplication, division and mod operator				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Count number of bits to be flipped to convert A to B				Save Notes	Medium
	Find the number that appears odd number of times				Save Notes	Easy
	Power Set				Save Notes	Medium
	Find xor of numbers from L to R				Save Notes	Easy
	Find the two numbers appearing odd number of times				Save Notes	Easy

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Print Prime Factors of a Number				Save Notes	Easy
	All Divisors of a Number				Save Notes	Easy
	Sieve of Eratosthenes				Save Notes	Medium
	Find Prime Factorisation of a Number using Sieve				Save Notes	Medium
	Power(n, x)				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Implement Stack using Arrays				Save Notes	Easy
	Implement Queue using Arrays				Save Notes	Easy
	Implement Stack using Queue				Save Notes	Medium
	Implement Queue using Stack				Save Notes	Medium
	Implement stack using Linkedlist				Save Notes	Easy
	Implement queue using Linkedlist				Save Notes	Medium
	Check for balanced paranthesis				Save Notes	Medium
	Implement Min Stack				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Infix to Postfix Conversion using Stack				Save Notes we ignored the right to left associativity of ^.\nas if we not ignored then if top of stack have ^ and new operator is also ^.\nthen instead of pop of ^ from stack we push the new ^ into the stack wothout poppinf ^ as \nnew ^ and old ^ are same then have to decide presendece using associative and it is right to left means in original equation new ^(just scanned ) is in right side od the old ^ (in top of stack), so this new^ have more presendce so without poping old ^ out, we can push it in.\n\n\nas for all operator the fall in same presendece groupt all have same associativit either left to right or right to left \nmeans have to compare which have more presedence(which operatoe whould be solved first) then we use associativity. if it is not and two operator which are in same presendece group and have diffrent associative like op1 have left to right and op2 have right to left then\n\nE : a op1 b op2 c.\nwe can not decide which one solve first op1 or op2.\nas both are in same presedence set and op1 will say i have left presendce and i am left to op2 so solve me first, so \nop2 will also say that i have right to left presedence and i am at right to op1 so solve me first.\n\nso we can not decide. SO FOR ALL OPERATOR WHICH COMES IN SAME PRESEDENCE SET HAVE SAME TYPE OF ASSOCIATIVITY EITHER LEFT TO RIGHT OR RIGHT TO LEFT.	Medium
	Prefix to Infix Conversion				Save Notes st : A,B and OP : + => st: (B+A),in stack order of operand is reversed\nDO NOT FORGET TO ADD BRACKETS	Medium
	Prefix to Postfix Conversion				Save Notes for loop start from last and \nans : A,B => a==A and b==B after poping 2 operand from stack\nnow as it is from prefix, implies we push in reverse order b+a+ operator	Medium
	Postfix to Prefix Conversion				Save Notes for loop start from 0 and \nans : A,B => a==A and b==B after poping 2 operand from stack\nnow as it is from postfix, implies we push in same order operator+a+b	Medium
	Postfix to Infix				Save Notes st : A,B and OP : + => st: A+B,in stack order of operand is same\nDO NOT FORGET TO ADD BRACKETS	Medium
	Convert Infix To Prefix Notation				Save Notes most partis same as infix to postfix just new 3 things have to see\n1. reverse the given string first and then replace (-->) and )-->(.\nEx: E = A+B(C-D)\nafter reverse E : )D-C(B+A\nafter replace (-->) && )-->( E :(D-C)B+A.\nnow consider this as initial string\n\n2. do infix to postfix of new string in a controlled manner\nWHAT IS CONTROLLED\nok it is nothing but logically seeing prsedence using associativity as we reveresd the string first all pair of operater's place is changed. \nthe one who was in right comes to left and left one comes to right.\nso here string is reversed we have to reverse the associtivity as (left to right) swapped with (right to left)\nin genereal ^ have RIGHT TO LEFT associativity but here consider it LEFT TO RIGHT &&\nin genereal +,-,,/ have LEFT TO RIGHT associativity but here consider it RIGHT TO LEFT\n\nso if top of stack have ^ and new operater id ^ then stack's ^ have more presedence so pop ^ from stack and add it to answer and inset our new ^ to stack &&\nif top of stack is + or - and new operator is + or - then new operator have more presedence so push it in stack without poping\nsame goes for *and/\n\n3. after getting the ans just reverse it as reversed in step 1. first reverse the string and then replace ( to ) and ) to (.\nand then retuen the answer	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Next Greater Element				Save Notes	Easy
	Next Greater Element 2				Save Notes	Medium
	Next Smaller Element				Save Notes	Easy
	Number of NGEs to the right				Save Notes	Easy
	Trapping Rainwater				Save Notes	Hard
	Sum of subarray minimum				Save Notes	Medium
	Asteroid Collision				Save Notes	Medium
	Sum of subarray ranges				Save Notes	Medium
	Remove k Digits				Save Notes	Medium
	Largest rectangle in a histogram				Save Notes	Medium
	Maximal Rectangles				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Sliding Window maximum				Save Notes	Hard
	Stock span problem				Save Notes	Medium
	The Celebrity Problem				Save Notes https://www.geeksforgeeks.org/problems/the-celebrity-problem/1	Hard
	LRU cache (IMPORTANT)				Save Notes	Hard
	LFU cache				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Longest Substring Without Repeating Characters				Save Notes	Medium
	Max Consecutive Ones III				Save Notes	Medium
	Fruit Into Baskets				Save Notes	Medium
	longest repeating character replacement				Save Notes	Medium
	Binary subarray with sum				Save Notes	Easy
	Count number of nice subarrays				Save Notes	Medium
	Number of substring containing all three characters				Save Notes	Medium
	Maximum point you can obtain from cards				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Longest Substring with At Most K Distinct Characters				Save Notes https://www.naukri.com/code360/problems/distinct-characters_2221410	Medium
	Subarray with k different integers				Save Notes same as in question https://leetcode.com/problems/binary-subarrays-with-sum/ where we find the answer for <=k and then for <=k-1\nas it is easy to find and then just subtract \nand for count of unique just check for map when it is going to increase from 0 and decrease to 0 give us chage in count as same as in https://www.naukri.com/code360/problems/distinct-characters_2221410	Hard
	Minimum Window Substring				Save Notes	Hard
	Minimum Window Subsequence				Save Notes https://www.geeksforgeeks.org/problems/minimum-window-subsequence/0\nhttps://www.naukri.com/code360/problems/minimum-window-subsequence_2181133	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Introduction to Priority Queues using Binary Heaps				Save Notes https://www.geeksforgeeks.org/problems/implementation-of-priority-queue-using-binary-heap/1	Medium
	Min Heap and Max Heap Implementation				Save Notes https://www.geeksforgeeks.org/problems/operations-on-binary-min-heap/1	Medium
	Check if an array represents a min-heap or not				Save Notes https://www.geeksforgeeks.org/problems/does-array-represent-heap4345/1	Medium
	Convert min Heap to max Heap				Save Notes https://www.geeksforgeeks.org/problems/convert-min-heap-to-max-heap-1666385109/1	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Kth largest element in an array [use priority queue]				Save Notes	Easy
	Kth smallest element in an array [use priority queue]				Save Notes	Easy
	Sort K sorted array				Save Notes	Easy
	Merge M sorted Lists				Save Notes	Hard
	Replace each array element by its corresponding rank				Save Notes	Easy
	Task Scheduler				Save Notes	Medium
	Hands of Straights				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Design twitter				Save Notes	Medium
	Connect `n` ropes with minimal cost				Save Notes https://www.geeksforgeeks.org/problems/minimum-cost-of-ropes-1587115620/1	Medium
	Kth largest element in a stream of running integers				Save Notes	Easy
	Maximum Sum Combination				Save Notes	Medium
	Find Median from Data Stream				Save Notes	Hard
	K most frequent elements				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Assign Cookies				Save Notes	Easy
	Fractional Knapsack Problem				Save Notes	Medium
	Greedy algorithm to find minimum number of coins				Save Notes https://www.geeksforgeeks.org/problems/number-of-coins1824/1\nIt's not Greedy it is of DP	Medium
	Lemonade Change				Save Notes	Easy
	Valid Paranthesis Checker				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	N meetings in one room				Save Notes	Medium
	Jump Game				Save Notes	Medium
	Jump Game 2				Save Notes	Medium
	Minimum number of platforms required for a railway				Save Notes	Medium
	Job sequencing Problem				Save Notes	Medium
	Candy				Save Notes	Hard
	Program for Shortest Job First (or SJF) CPU Scheduling				Save Notes	Medium
	Program for Least Recently Used (LRU) Page Replacement Algorithm				Save Notes	Medium
	Insert Interval				Save Notes	Medium
	Merge Intervals				Save Notes	Medium
	Non-overlapping Intervals				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Introduction to Trees				Save Notes	Easy
	Binary Tree Representation in C++				Save Notes	Easy
	Binary Tree Representation in Java				Save Notes	Easy
	Binary Tree Traversals in Binary Tree				Save Notes	Easy
	Preorder Traversal of Binary Tree				Save Notes	Easy
	Inorder Traversal of Binary Tree				Save Notes	Easy
	Post-order Traversal of Binary Tree				Save Notes	Easy
	Level order Traversal / Level order traversal in spiral form				Save Notes	Easy
	Iterative Preorder Traversal of Binary Tree				Save Notes	Easy
	Iterative Inorder Traversal of Binary Tree				Save Notes	Easy
	Post-order Traversal of Binary Tree using 2 stack				Save Notes	Easy
	Post-order Traversal of Binary Tree using 1 stack				Save Notes https://www.geeksforgeeks.org/problems/postorder-traversal-iterative/1	Medium
	Preorder, Inorder, and Postorder Traversal in one Traversal				Save Notes https://www.naukri.com/code360/problems/tree-traversal_981269\nthis is the real problem	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Height of a Binary Tree				Save Notes	Medium
	Check if the Binary tree is height-balanced or not				Save Notes	Medium
	Diameter of Binary Tree				Save Notes	Medium
	Maximum path sum				Save Notes	Hard
	Check if two trees are identical or not				Save Notes	Medium
	Zig Zag Traversal of Binary Tree				Save Notes	Easy
	Boundary Traversal of Binary Tree				Save Notes https://www.naukri.com/code360/problems/boundary-traversal_790725	Medium
	Vertical Order Traversal of Binary Tree				Save Notes	Easy
	Top View of Binary Tree				Save Notes	Easy
	Bottom View of Binary Tree				Save Notes	Medium
	Right/Left View of Binary Tree				Save Notes	Medium
	Symmetric Binary Tree				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Root to Node Path in Binary Tree				Save Notes https://www.naukri.com/code360/problems/path-in-a-tree_3843990	Medium
	LCA in Binary Tree				Save Notes	Medium
	Maximum width of a Binary Tree				Save Notes	Medium
	Check for Children Sum Property				Save Notes https://www.naukri.com/code360/problems/childrensumproperty_790723	Hard
	Print all the Nodes at a distance of K in a Binary Tree				Save Notes	Medium
	Minimum time taken to BURN the Binary Tree from a Node				Save Notes	Hard
	Count total Nodes in a COMPLETE Binary Tree				Save Notes	Medium
	Requirements needed to construct a Unique Binary Tree \| Theory				Save Notes	Medium
	Construct Binary Tree from inorder and preorder				Save Notes	Hard
	Construct the Binary Tree from Postorder and Inorder Traversal				Save Notes	Hard
	Serialize and deserialize Binary Tree				Save Notes	Hard
	Morris Preorder Traversal of a Binary Tree				Save Notes https://leetcode.com/problems/binary-tree-preorder-traversal/description/	Medium
	Morris Inorder Traversal of a Binary Tree				Save Notes	Medium
	Flatten Binary Tree to LinkedList				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Introduction to Binary Search Tree				Save Notes	Easy
	Search in a Binary Search Tree				Save Notes	Easy
	Find Min/Max in BST				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Ceil in a Binary Search Tree				Save Notes	Easy
	Floor in a Binary Search Tree				Save Notes	Easy
	Insert a given Node in Binary Search Tree				Save Notes	Easy
	Delete a Node in Binary Search Tree				Save Notes	Medium
	Find K-th smallest/largest element in BST				Save Notes	Medium
	Check if a tree is a BST or BT				Save Notes	Medium
	LCA in Binary Search Tree				Save Notes	Medium
	Construct a BST from a preorder traversal				Save Notes	Medium
	Inorder Successor/Predecessor in BST				Save Notes https://www.naukri.com/code360/problems/_893049\nhttps://www.geeksforgeeks.org/problems/predecessor-and-successor/1	Medium
	Merge 2 BST's				Save Notes	Hard
	Two Sum In BST \| Check if there exists a pair with Sum K				Save Notes	Medium
	Recover BST \| Correct BST with two nodes swapped				Save Notes	Hard
	Largest BST in Binary Tree				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Graph and Types				Save Notes	Easy
	Graph Representation \| C++				Save Notes https://www.naukri.com/code360/problems/create-a-graph-and-print-it_1214551	Easy
	Graph Representation \| Java				Save Notes	Easy
	Connected Components \| Logic Explanation				Save Notes	Hard
	BFS				Save Notes https://www.naukri.com/code360/problems/bfs-in-graph_973002	Medium
	DFS				Save Notes https://www.naukri.com/code360/problems/dfs-traversal_630462	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Word ladder - 1				Save Notes https://www.naukri.com/code360/problems/word-ladder_1102319	Hard
	Word ladder - 2				Save Notes	Hard
	Number of Distinct Islands [dfs multisource]				Save Notes https://www.naukri.com/code360/problems/largest-island_840701	Hard
	Bipartite Graph (DFS)				Save Notes https://www.naukri.com/code360/problems/check-graph-is-bipartite-or-not_920551	Medium
	Cycle Detection in Directed Graph (DFS)				Save Notes https://www.naukri.com/code360/problems/detect-cycle-in-a-directed-graph_1062626\nhttps://www.naukri.com/code360/problems/detect-cycle-in-a-directed-graph_920545	Hard
	Number of provinces (leetcode)				Save Notes https://www.naukri.com/code360/problems/find-the-number-of-states_1377943	Medium
	Connected Components Problem in Matrix				Save Notes	Hard
	Rotten Oranges				Save Notes https://www.naukri.com/code360/problems/rotting-oranges_701655	Medium
	Flood fill				Save Notes https://www.naukri.com/code360/problems/flood-fill-algorithm_1089687	Hard
	Cycle Detection in unirected Graph (bfs)				Save Notes https://www.naukri.com/code360/problems/detect-cycle-in-an-undirected-graph_758967	Hard
	Cycle Detection in undirected Graph (dfs)				Save Notes https://www.naukri.com/code360/problems/detect-cycle-in-an-undirected-graph_758967	Hard
	0/1 Matrix (Bfs Problem)				Save Notes https://www.naukri.com/code360/problems/distance-of-nearest-cell-having-1-in-a-binary-matrix_1169913	Medium
	Surrounded Regions (dfs)				Save Notes https://www.naukri.com/code360/problems/replace-o-with-x_630517	Hard
	Number of Enclaves [flood fill implementation - multisource]				Save Notes https://www.naukri.com/code360/problems/number-of-islands_845181	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Topo Sort				Save Notes https://www.naukri.com/code360/problems/topological-sorting_973003	Hard
	Kahn's Algorithm				Save Notes https://www.naukri.com/code360/problems/topological-sort_982938	Hard
	Cycle Detection in Directed Graph (BFS)				Save Notes https://www.naukri.com/code360/problems/detect-cycle-in-a-directed-graph_920545	Hard
	Course Schedule - I				Save Notes https://www.naukri.com/code360/problems/course-schedule_985288	Hard
	Course Schedule - II				Save Notes https://www.naukri.com/code360/problems/course-schedule-ii_1069243	Hard
	Find eventual safe states				Save Notes https://www.naukri.com/code360/problems/safe-nodes-in-the-graph_1376703	Hard
	Alien dictionary				Save Notes https://www.geeksforgeeks.org/problems/alien-dictionary/1\nhttps://www.naukri.com/code360/problems/alien-dictionary_630423	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Shortest Path in UG with unit weights				Save Notes https://www.naukri.com/code360/problems/saving-money_1171195	Hard
	Shortest Path in DAG				Save Notes	Hard
	Djisktra's Algorithm				Save Notes https://www.naukri.com/code360/problems/dijkstra-s-shortest-path_985358	Hard
	Why priority Queue is used in Djisktra's Algorithm				Save Notes	Medium
	Shortest path in a binary maze				Save Notes	Medium
	Path with minimum effort				Save Notes https://www.naukri.com/code360/problems/path-with-minimum-effort_1380958	Medium
	Cheapest flights within k stops				Save Notes	Hard
	Network Delay time				Save Notes https://www.naukri.com/code360/problems/network-delay-time_1382215	Medium
	Number of ways to arrive at destination				Save Notes	Medium
	Minimum steps to reach end from start by performing multiplication and mod operations with array elements				Save Notes	Hard
	Bellman Ford Algorithm				Save Notes https://www.naukri.com/code360/problems/bellmon-ford_2041977\n\nadd dis[u]!=1e9 to escape irrelavent neighbour vertex update, because of -ve weight	Hard
	Floyd Warshal Algorithm				Save Notes https://www.naukri.com/code360/problems/flloyd-warshall_2041979	Hard
	Find the city with the smallest number of neighbors in a threshold distance				Save Notes https://www.naukri.com/code360/problems/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance_1264289	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Minimum Spanning Tree				Save Notes https://www.naukri.com/code360/problems/minimum-spanning-tree_631769	Hard
	Prim's Algorithm				Save Notes	Hard
	Disjoint Set [Union by Rank]				Save Notes gfg ka question prompt hi chutiya h \nultimate parent ki jagh sirf parent bol rahe and array me sub sorted h then A[0]==1 hona chayie na ki A[1]==1.\nBSDK	Hard
	Disjoint Set [Union by Size]				Save Notes	Hard
	Kruskal's Algorithm				Save Notes https://www.naukri.com/code360/problems/kruskal-s-minimum-spanning-tree-algorithm_1082553	Hard
	Number of operations to make network connected				Save Notes	Medium
	Most stones removed with same rows or columns				Save Notes	Medium
	Accounts merge				Save Notes	Hard
	Number of island II				Save Notes https://www.naukri.com/code360/problems/largest-island_840701	Hard
	Making a Large Island				Save Notes	Hard
	Swim in rising water				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Bridges in Graph				Save Notes https://www.naukri.com/code360/problems/bridges-in-graph_893026	Hard
	Articulation Point				Save Notes	Hard
	Kosaraju's Algorithm				Save Notes https://www.naukri.com/code360/problems/count-strongly-connected-components-kosaraju-s-algorithm_1171151	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Dynamic Programming Introduction				Save Notes https://www.geeksforgeeks.org/problems/introduction-to-dp/1	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Climbing Stars				Save Notes	Medium
	Frog Jump(DP-3)				Save Notes https://www.naukri.com/code360/problems/frog-jump_3621012	Medium
	Frog Jump with k distances(DP-4)				Save Notes	Medium
	Maximum sum of non-adjacent elements (DP 5)				Save Notes https://www.naukri.com/code360/problems/maximum-sum-of-non-adjacent-elements_843261	Medium
	House Robber (DP 6)				Save Notes https://www.naukri.com/code360/problems/house-robber_839733	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Ninja's Training (DP 7)				Save Notes https://www.naukri.com/code360/problems/ninja-and-his-friends_3125885	Medium
	Grid Unique Paths : DP on Grids (DP8)				Save Notes https://www.naukri.com/code360/problems/total-unique-paths_1081470	Medium
	Grid Unique Paths 2 (DP 9)				Save Notes https://www.naukri.com/code360/problems/maze-obstacles_977241	Medium
	Minimum path sum in Grid (DP 10)				Save Notes https://www.naukri.com/code360/problems/minimum-path-sum_985349	Medium
	Minimum path sum in Triangular Grid (DP 11)				Save Notes https://www.naukri.com/code360/problems/triangle_1229398	Medium
	Minimum/Maximum Falling Path Sum (DP-12)				Save Notes https://www.naukri.com/code360/problems/maximum-path-sum-in-the-matrix_797998	Medium
	3-d DP : Ninja and his friends (DP-13)				Save Notes https://www.naukri.com/code360/problems/ninja-and-his-friends_3125885	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Subset sum equal to target (DP- 14)				Save Notes	Medium
	Partition Equal Subset Sum (DP- 15)				Save Notes	Medium
	Partition Set Into 2 Subsets With Min Absolute Sum Diff (DP- 16)				Save Notes	Medium
	Count Subsets with Sum K (DP - 17)				Save Notes	Medium
	Count Partitions with Given Difference (DP - 18)				Save Notes	Medium
	Assign Cookies				Save Notes	Hard
	Minimum Coins (DP - 20)				Save Notes	Hard
	Target Sum (DP - 21)				Save Notes	Medium
	Coin Change 2 (DP - 22)				Save Notes	Hard
	Unbounded Knapsack (DP - 23)				Save Notes this question and above coin change 2 both are of same type as in both for a element infinite supply was given \nso when things like this happen we go through first by each element and find all best answer by this and \nON UPDATING WEIGHT or SUM on take case: we take value from same i or row because taking from previous row only mean that there is no infinite supply.\nso here we have to run loop from j=arr[i] to sum and update from same row.\nfor(int i=0;i<N;i++){\n for(int j=wt[i];j<=W;j++)\n dp[j]=max(dp[j],dp[j-wt[i]]+val[i]);\n}\nhere for i th element it update all the best sum possible\nand after going to next i we don't take this i back.\nSUM wala loop to andar hi chalega bus infinite supply me sidha chalega nhi to ulta chalega	Hard
	Rod Cutting Problem \| (DP - 24)				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Longest Common Subsequence \| (DP - 25)				Save Notes	Hard
	Print Longest Common Subsequence \| (DP - 26)				Save Notes https://www.geeksforgeeks.org/problems/print-all-lcs-sequences3413/1	Hard
	Longest Common Substring \| (DP - 27)				Save Notes https://www.geeksforgeeks.org/problems/longest-common-substring1452/1 \nfor(int i=1;i<=n1;i++){\n for(int j=n2;j>0;j--)if(str1[i-1]==str2[j-1]){\n dp[j]=dp[j-1]+1;\n ans=max(ans,dp[j]);\n }else dp[j]=0;\n }\n\nhave to add this else statement to reset the value that come from prvious computation if we have no else condition we have to make if we want to do it in single or double 1d dp.\nelse dp[j]=0;	Hard
	Longest Palindromic Subsequence \| (DP-28)				Save Notes	Hard
	Minimum insertions to make string palindrome \| DP-29				Save Notes	Hard
	Minimum Insertions/Deletions to Convert String \| (DP- 30)				Save Notes	Hard
	Shortest Common Supersequence \| (DP - 31)				Save Notes	Hard
	Distinct Subsequences\| (DP-32)				Save Notes https://www.geeksforgeeks.org/problems/number-of-distinct-subsequences0909/1\nhttps://www.naukri.com/code360/problems/distinct-subsequences_799558	Hard
	Edit Distance \| (DP-33)				Save Notes	Hard
	Wildcard Matching \| (DP-34)				Save Notes	Medium

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Best Time to Buy and Sell Stock \|(DP-35)				Save Notes	Hard
	Buy and Sell Stock - II\|(DP-36)				Save Notes	Hard
	Buy and Sell Stocks III\|(DP-37)				Save Notes loop should be run from last to first as it is stock problem	Hard
	Buy and Stock Sell IV \|(DP-38)				Save Notes	Hard
	Buy and Sell Stocks With Cooldown\|(DP-39)				Save Notes	Hard
	Buy and Sell Stocks With Transaction Fee\|(DP-40)				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Longest Increasing Subsequence \|(DP-41)				Save Notes TOTAL 3 CODES\ncode 1 sabse chutiya code, bhul jai ise, yadd nhi karoge tab bhi chalega\nclass Solution\n{\n public:\n int longestSubsequence(int n, int a[]){\n vector<int>dp(n+1,0);\n for(int i=n-1;i>=0;i--){\n for(int prev = i-1;prev>=-1;prev--){\n int len = dp[prev+1];\n if(prev==-1 \|\| a[prev]<a[i]){\n len = max(len,1+dp[i+1]);\n }\n dp[prev+1]=len;\n }\n }\n return dp[0];\n }\n};\n\n\n\n\n\n\n\ncode 2 sabse best code in TC = O(NN)\n\nclass Solution {\npublic:\n int lengthOfLIS(vector<int>& v) {\n int n=v.size();\n vector<int>dp(n,1);\n int ans=1;\n for(int i=0;i<n;i++){\n for(int j=0;j<i;j++){\n if(v[j]<v[i] && dp[j]+1>dp[i]){\n dp[i]++;\n ans = max(ans,dp[i]);\n }\n }\n }\n return ans;\n\n }\n};\n\n\n\ncode 3. Only for length TC= O(NLog(N))\nclass Solution {\npublic:\n int lengthOfLIS(vector<int>& v) {\n int n=v.size();\n vector<int>dp(n,1);\n int ans=1;\n for(int i=0;i<n;i++){\n for(int j=0;j<i;j++){\n if(v[j]<v[i] && dp[j]+1>dp[i]){\n dp[i]++;\n ans = max(ans,dp[i]);\n }\n }\n }\n return ans;\n\n }\n};	Hard
	Printing Longest Increasing Subsequence\|(DP-42)				Save Notes https://www.geeksforgeeks.org/problems/printing-longest-increasing-subsequence/1	Hard
	Longest Increasing Subsequence \|(DP-43)				Save Notes https://www.geeksforgeeks.org/problems/longest-increasing-subsequence-1587115620/1	Hard
	Largest Divisible Subset\|(DP-44)				Save Notes	Hard
	Longest String Chain\|(DP-45)				Save Notes	Hard
	Longest Bitonic Subsequence \|(DP-46)				Save Notes https://www.geeksforgeeks.org/problems/longest-bitonic-subsequence0824/1	Hard
	Number of Longest Increasing Subsequences\|(DP-47)				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Matrix Chain Multiplication\|(DP-48)				Save Notes https://www.geeksforgeeks.org/problems/matrix-chain-multiplication0303/1	Hard
	Matrix Chain Multiplication \| Bottom-Up\|(DP-49)				Save Notes https://www.geeksforgeeks.org/problems/matrix-chain-multiplication0303/1\nconversion of recursion Matrix Multiplication into Tabulation\n\nreturn fn(1,N-1,arr,dp);\nwe called this in recursion here \ni was 1 so it goes from 1 to N-1 in recursion so we need to calculate it from N-1 to 1 in tabulation form\nand J goes from N-1 to 1 so in tabulation it will be from 1 to N-1 but j is always greater then i so it will go from i+1 to N-1\n\nfor (int i=N-1;i>=1;i--){\n for(int j=i+1;j<=N-1;j++{\n\n }\n}\nthat's how it will be done	Hard
	Minimum Cost to Cut the Stick\|(DP-50)				Save Notes	Hard
	Burst Balloons\|(DP-51)				Save Notes	Hard
	Evaluate Boolean Expression to True\|(DP-52)				Save Notes https://www.naukri.com/code360/problems/problem-name-boolean-evaluation_1214650	Hard
	Palindrome Partitioning - II\|(DP-53)				Save Notes	Hard
	Partition Array for Maximum Sum\|(DP-54)				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Maximum Rectangle Area with all 1's\|(DP-55)				Save Notes https://leetcode.com/problems/largest-rectangle-in-histogram/	Hard
	Count Square Submatrices with All Ones\|(DP-56)				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Implement TRIE \| INSERT \| SEARCH \| STARTSWITH				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Implement Trie - 2 (Prefix Tree)				Save Notes https://www.naukri.com/code360/problems/implement-trie_1387095	Hard
	Longest String with All Prefixes				Save Notes https://www.naukri.com/code360/problems/complete-string_2687860	Medium
	Number of Distinct Substrings in a String				Save Notes https://www.naukri.com/code360/problems/count-distinct-substrings_985292	Hard
	Bit PreRequisites for TRIE Problems				Save Notes	Hard
	Maximum XOR of two numbers in an array				Save Notes	Medium
	Maximum XOR With an Element From Array				Save Notes	Hard

Status	Problem	Article	Youtube	Practice	Note	Difficulty	Revision
	Minimum number of bracket reversals needed to make an expression balanced				Save Notes	Medium
	Count and say				Save Notes	Medium
	Hashing In Strings \| Theory				Save Notes	Medium
	Rabin Karp				Save Notes	Hard
	Z-Function				Save Notes	Easy
	KMP algo / LPS(pi) array				Save Notes https://www.geeksforgeeks.org/problems/search-pattern0205/1	Hard
	Shortest Palindrome				Save Notes #include<bits/stdc++.h> using namespace std; int main(){ string b = ""ababbbabbaba""; int n = b.size(); int lms[n]; lms[0]=0; int len=0,i=1; while(i<n){ if(b[i]==b[len]){ len++; lms[i]=len; i++; }else if(len>0){ len = lms[len-1]; }else{ lms[i]=0; i++; } } int lps[n]; lps[0]=0; len=0,i=1; while(i<n){ if(b[i]==b[len]){ len++; lps[i]=len; i++; }else if(len>0){ len--; }else{ lps[i]=0; i++; } } cout<<""string : ""; for(auto it:b)cout<<it<<"" ""; cout<<endl; cout<<""right : ""; for(auto it:lms)cout<<it<<"" ""; cout<<endl; cout<<""wrong : ""; for(auto it:lps)cout<<it<<"" ""; cout<<endl; return 0; } string : a b a b b b a b b a b a right : 0 0 1 2 0 0 1 2 0 1 2 3 wrong : 0 0 1 2 2 2 3 4 5 3 4 3	Hard
	Longest happy prefix				Save Notes	Hard
	Count palindromic subsequence in given string				Save Notes https://www.geeksforgeeks.org/problems/count-palindromic-subsequences/1	Hard